Formulas - More Totals

Lets say you need to total numbers that are not in a range, example a1, a5, a10. Well normally the formula would be =a1+a5+a10. If you have 10 cells to total up that would be slow coz you need to type in "+". Next time try using type =sum( first, then hold down the control key, use the mouse & click on a1, a5, a10, then release the control key and type ) and you're done! The formula would be =sum(a1,a5,a10) Fast wasn't it?